In recent years it has become increasing popular to cultivate marine species in controlled settings. This cultivation, which is commonly referred to as aquaculture, has allowed the production of a variety of marine species for human consumption. Increasingly, many edible fishes have been produced using aquaculture. While aquaculture has shown marked technological increases, to support the growth of this industry, it is necessary to produce an artificial feed or to increase the harvest of naturally occurring foodstuff such as Artemia, Brachinus salina, Daphnia, etc.
All marine life in the seas ultimately depends on microscopic algae for their growth or the growth of their food within the marine food chain. This microscopic algae, which is the first link within the marine food chain, is directly consumed by filter feeders such as shell fish, and indirectly through the complex food chain within the sea by the rest of marine life. Algae grows very slowly, however, as they only divide approximately once a day and therefore they are not easily available. This lack of availability contributes to a significant increase in the cost of aquaculture products.
Attempts to replicate or replace natural foodstuff within aquaculture have been met with limited success. In U.S. Pat. No. 5,158,788 to Lavens et al. (“Lavens”), a method is described to produce a feed for aquaculture from yeast. Lavens entails a multi-step process in which yeast cells are processed by hydrolyzing its cell wall producing a digestible feed for aquaculture. Unfortunately, the multi-step process as suggested by Lavens is labor intensive and therefore not feasible economically. Most importantly, the destruction of the cell wall that is needed to produce this artificial feed causes pollution of the aquaculture by the cell materials contained within the yeast cell.
One significant natural food source within the marine food chain that feeds off microscopic algae is Artemia. Artemia commonly referred to as brine shrimp is an excellent foodstuff for aquaculture, because of its position within the marine food chain and its desirability as a food source for higher members of marine culture. They are an excellent food for aquaculture, because unlike prior art foods in aquaculture they do not undergo putrefaction by microorganisms and foul water used in aquaculture, but rather they clear the water of fouling micro-organisms. It is commonly known that Artemia can be used as a feed for species such as shrimp, fishes, etc.
The natural harvesting of Artemia for their use in aquaculture, however, is subject to environmental factors that have recently led to shortages. Artemia grow in large saline lakes such as the Great Salt Lake in Utah. Artemia have been harvested in the Great Salt Lake for many years. Unfortunately, recent harvests have been poor and the cost of Artemia cysts has increased more than three fold. It is thought that these recent poor harvests have been caused by changing weather patterns. Severe climatic disturbances caused by the warm weather and excessive rainfall that accompanied El Nino caused production levels of the Artemia from the Great Salt Lake to decrease dramatically. The harvest of Artemia cysts in 1995-96 and 1996-97 was approximately 15 million pounds gross weight. Of this total harvest only about fifty percent is suitable for use. The 1997-98 harvest was only approximately 6 million pounds gross weight. Decreases in harvesting of Artemia cysts, such as in the case of El Nino, not only cause problems with availability, but also sharp increases in the price of Artemia cysts. This sharp increase in cost makes the use of Artemia as a feed for aquaculture economically impermissible.
Although there are several other sources of Artemia throughout the world, the Great Salt Lake provides more than ninety percent of the world's Aretmia cyst consumption. While additional sources of Artemia have been found in Russia, Turkey, and China, these additional sources have not offset the declining harvest of the Great Salt Lake. Various methods of producing Artemia within aquaculture have been explored such as in Vietnam, where Artemia have been growth in ponds having abundance of natural algae. In Hawaii, yeast and greenwater have been used to grow Artemia and rotifers for seahorse and Asian sea bass aquaculture. Unfortunately, these various efforts have been met with limited success as these prior methods of producing Artemia are labor extensive and not economically feasible.